1. Field of the Invention
The present invention relates to a wood chipping machine for chipping a flat face on a log, cant or other piece of wood and simultaneously smoothing the flat face thus formed while producing usable wood chips and shavings in the process.
2. Description of the Prior Art
Formerly, logs were flattened along one or more sides by sawing slabs from them as they moved relative to the saw. Once flattened, the resulting cants, or boards sawn from the cants, would be planned on all four sides to yield finished dimension lumber. If unfinished or "rough sawn" lumber were desired, the planing operation could be eliminated.
The resulting slabs had to be conveyed to a separate location and either burned as waste, ground into hog fuel for the mill's boilers, or reduced to marketable pulp chips in a separate chipping operation.
Subsequently, it became feasible to combine a rotary chipping head with a saw blade so that the slab was chipped as the log was flattened on one face, as shown by U.S. Pat. No. 3,780,778. One drawback to this approach, however, was that it introduced sawdust into the chips, reducing their quality and acceptability as pulp feed stock.
Another drawback to the combination saw and rotary chipper involved maintenance. The saw blades dulled rapidly, necessitating their replacement and resharpening. Because of the peculiar design of such devices, this was a tedious process and involved additional labor costs to resharpen the blades and to remove and replace them on the machine. It also required much down time for the machine, resulting in loss of productivity.
The development of improved rotary chipping heads enabled deletion of the saw blade. However, such chipping heads formed a flat face on the workpiece that was still too rough to enable use of the resulting boards or timbers even as rough-sawn lumber without a subsequent planing operation.
Accordingly, there is a need for an improved rotary chipping head capable of flattening a face of a log or other wood member while leaving such face acceptably smooth, without the use of rapidly dulling saws and without the need for a subsequent planing operation, and while producing usable pulp chips.